The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Traditional engine control systems are limited in accurately controlling engine torque output. The traditional engine control systems are also slow to respond to received control signals and limited in coordinate engine torque control with respect to various devices that affect engine torque output.
Powertrain control systems include various modules that require a certain amount of engine torque to operate properly. For example, an automatic transmission control module may need to momentarily reduce torque from the engine in order to change transmission gears. Another example is an air conditioning clutch control module that needs a momentary increase in engine torque before engaging an air conditioning compressor clutch. The engine torque increase helps maintain a constant engine speed when the compressor clutch engages, such as when the engine is idling.
Traditionally, the various modules affect torque actuators directly. For example, the automatic transmission control module may retard a spark advance to the engine to reduce the engine torque during the shift. Similarly, the air conditioning clutch control module may increase the spark advance to increase the engine torque during the moment prior to engaging the compressor clutch.
As vehicle powertrain systems include more modules and more actuators that affect torque, the architecture of the prior art becomes cumbersome to maintain and undesirably difficult to troubleshoot. As an example of more actuators, hybrid vehicles include an engine and an electric motor that provide torque. Integrating the hybrid vehicle powertrain to existing torque-modifying modules can be undesirably cumbersome with traditional powertrain control architectures.
Coordinated torque control (CTC) systems have been developed to accurately control engine output torque. An example torque control system is disclosed in commonly assigned U.S. Pat. No. 7,021,282 (“Coordinated Engine Torque Control”). CTC systems provide a rapid response to control signals and coordinate engine torque control based on various devices that affect engine torque output.